   (apply min (map (fn [msg] (:id msg)) @all-msgs)))
 (defn clear-old-msgs []
   (let [min-id (min-clients-last-id)]
-    (dosync (ref-set all-msgs (filter (fn [msg] (>= (:id msg) (- min-id 10))) @all-msgs)))))
+    (dosync
+      (ref-set all-msgs (filter (fn [msg] (>= (:id msg) (- min-id 10))) @all-msgs))
+      (let [total (count @all-msgs)]
+        (if (> total 4096)
+          (ref-set all-msgs (vec (drop (- total 4096) @all-msgs)))
+          (ref-set all-msgs @all-msgs))))))
+(def not-nil? (complement nil?))
 ; multi method, dispatch by command and version
 (defn dispatcher [packet channel] [(:command packet) (:version packet)])
 (defmulti  process-packet dispatcher)

    (let [login (:data packet) id (- @max-id 20)]
      (swap! clients         assoc channel login)
      (swap! clients-last-id assoc channel id)
      (println packet @clients-last-id)
      (send! channel (json-str {:status "ok"}))
      (dosync (ref-set all-msgs (conj @all-msgs {:id (next-id) :time (now) :msg (format "Пришел: %s" (@clients channel)) :author "system"}))))))
; logout version 1
(defn logout [channel]
  (do
    (dosync (ref-set all-msgs (conj @all-msgs {:id (next-id) :time (now) :msg (format "Ушел: %s" (@clients channel)) :author "system"})))
    (swap! clients dissoc channel)
    (swap! clients-last-id dissoc channel)
    (println @clients-last-id)
    (clear-old-msgs)))
(defmethod process-packet ["logout" "1"] [packet channel]
  (do

    (let [author (@clients channel) text (strip-html-tags (:data packet))]
      (do
        (dosync (ref-set all-msgs (conj @all-msgs {:id (next-id) :time (now) :msg text :author author})))
        (send! channel (json-str {:status "ok"}))
        (clear-old-msgs)))))
; fetch version 1
(defmethod process-packet ["fetch" "1"] [packet channel]
  (let [last-id (@clients-last-id channel) cur-id (+ @max-id 1)]
    (do
      (if (not-nil? last-id)
        (do
          (send! channel
            (json-str {:status "ok" :data (sort-by :id < (filter (fn [msg] (>= (:id msg) last-id)) @all-msgs))}))
          (swap! clients-last-id assoc channel cur-id)
          (clear-old-msgs))))))
; perfomance dump version 1
